This invention relates to nucleic acid and amino acid sequences of new genes that are differentially expressed in cells that overexpress the Her-2/neu oncogene.
Cancers of the breast and ovary are among the leading causes of death among women. The cumulative lifetime risk of a woman developing breast cancer estimated to be 1 in 9. Consequently, understanding the origins of these malignancies as well as models for the identification of new diagnostic and therapeutic modalities is of significant interest to health care professionals. In this context, cancer cells have been shown to exhibit unique gene expression, and dozens of cancer-specific genetic markers, tumor antigens, have been identified.
The human HER-2/neu (c-erbB-2) proto-oncogene encodes a transmembrane receptor tyrosine kinase with extensive sequence homology to the epidermal growth factor receptor (EGFR) (Bargmann, C. I., Hung, M. C. and Weinberg, R. A. (1986) Cell, 45(5), 649-57). Amplification and/or overexpression of HER-2/neu has been found in one-third of human breast and one-fifth of ovarian cancers (Slamon, D. J., Clark, G. M., Wong, S. G., Levin, W. J., Ullrich, A. and McGuire, W. L. (1987) Science, 235(4785), 177-82Slamon, D. J., Godolphin, W., Jones, L. A., Holt, J. A., Wong, S. G., Keith, D. E., Levin, W. J., Stuart, S. G., Udove, J., Ullrich, A. and et al. (1989) Science, 244(4905), 707-12). In addition, the HER-2/neu alteration is associated with a poor clinical outcome in that women whose tumors contain it experience earlier disease relapse and shorter overall survival (Slamon, D. J., Godolphin, W., Jones, L. A., Holt, J. A., Wong, S. G., Keith, D. E., Levin, W. J., Stuart, S. G., Udove, J., Ullrich, A. and et al. (1989) Science, 244(4905), 707-12; O""Reilly, S. M., Barnes, D. M., Camplejohn, R. S., Bartkova, J., Gregory, W. M. and Richards, M. A. (1991) Br J Cancer, 63(3), 444-6; Press, M. F., Pike, M. C., Chazin, V. R., Hung, G., Udove, J. A., Markowicz, M., Danyluk, J., Godolphin, W., Sliwkowski, M., Akita, R. and et al. (1993) Cancer Res, 53(20), 4960-70; Seshadri, R., Horsfall, D. J., Firgaira, F., McCaul, K., Sedur, V., Chalmers, A. H., Yeo, R., Ingram, D., Dawkins, H. and Hahnel, R. (1994) Int J Cancer, 56(1), 61-5). Two hypotheses potentially account for this prognostic association. First, HER-2/neu overexpression may be an epiphenomenon serving merely as a marker of aggressive breast cancers. Conversely, the alteration may be causal for the aggressive phenotype. Considerable circumstantial evidence now supports the latter possibility, with data suggesting that overexpression plays a direct causal role in the pathogenesis of the malignancies in which it occurs (Shih, C., Padhy, L. C., Murray, M. and Weinberg, R. A. (1981) Nature, 290(5803), 261-4; Di Fiore, P. P., Pierce, J. H., Kraus, M. H., Segatto, O., King, C. R. and Aaronson, S. A. (1987) Science, 237(4811), 178-82; Hudziak, R. M., Schlessinger, J. and Ullrich, A. (1987) Proc Natl Acad Sci USA, 84(20), 7159-63).
The subtraction cloning technique termed differential hybridization, also known as plus/minus screening (St John, T. P. and Davis, R. W. (1979) Cell, 16(2), 443-52), can be used to isolate genes which are differentially expressed in cells which overexpress HER-2 as compared to control cells. This approach has the advantage of comparing two human breast cancer cell lines which are identical except for HER-2/neu overexpression allowing for a direct comparison of cDNAs derived from the two cell populations. As disclosed herein, using this approach, we identified a series of genes, either previously characterized or entirely novel, whose expression levels are altered in association with HER-2/neu overexpression. The evidence suggests that these genes might be mediators of the HER-2 overexpressing phenotype since we have confirmed their differential expression not only in human ovarian cancer cell lines which overexpress HER-2 but also primary breast cancer specimens containing this alteration.
The discovery of Her-2/neu overexpression modulated proteins, and the polynucleotides which encode them satisfies a need in the art by providing new compositions which have potential in understanding and modulating disorders associated with cell proliferation.
The present invention provides new Her-2/neu overexpression modulated proteins (including proteins having both new and known amino acid sequences such as novel splice variants of known proteins) hereinafter designated HOMPS. A first HOMPS protein is designated H17. The expression of H17 increases in cells which overexpress Her-2/neu. A second HOMPS protein is designated C40. The expression of C40 decreases in cells which overexpress Her-2/neu. A third HOMPS protein is designated H41. The expression of H41 increases in cells which overexpress Her-2/neu. A fourth HOMPS protein is designated H13. The expression of H13 increases in cells which overexpress Her-2/neu. A fifth HOMPS protein is designated H14. The expression of H14 increases in cells which overexpress Her-2/neu. In addition, the present invention discloses a HOMPS related polynucleotide sequence designated H63. The expression of H63 increases in cells which overexpress Her-2/neu.
The invention provides polynucleotides corresponding or complementary to all or part of the HOMPS genes, mRNAs, and/or coding sequences, preferably in isolated form, including polynucleotides encoding HOMPS proteins and fragments thereof, DNA, RNA, DNA/RNA hybrid, and related molecules, polynucleotides or oligonucleotides complementary to the HOMPS genes or mRNA sequences or parts thereof, and polynucleotides or oligonucleotides that hybridize to the HOMPS genes, mRNAs, or to HOMPS-encoding polynucleotides. Also provided are means for isolating cDNAs and the genes encoding HOMPS. Recombinant DNA molecules containing HOMPS polynucleotides, cells transformed or transduced with such molecules, and host-vector systems for the expression of HOMPS gene products are also provided. The invention further provides HOMPS proteins and polypeptide fragments thereof. The invention further provides antibodies that bind to HOMPS proteins and polypeptide fragments thereof, including polyclonal and monoclonal antibodies, murine and other mammalian antibodies, chimeric antibodies, humanized and fully human antibodies, and antibodies labeled with a detectable marker.
Accordingly, the invention provides a substantially purified HOMPS having the amino acid sequence shown in FIG. 2, FIG. 4, FIG. 6, FIG. 9 or FIG. 11. A typical embodiment of the invention provides an isolated and substantially purified polynucleotide that encodes HOMPS. In a particular aspect, the polynucleotide is the nucleotide sequence shown in FIG. 1, FIG. 3, FIG. 5, FIG. 8 or FIG. 10. The invention also provides a polynucleotide sequence comprising the complement of the nucleotide sequences shown in FIG. 1, FIG. 3, FIG. 5, FIG. 8 or FIG. 10 or variants thereof. In addition, the invention provides polynucleotide sequences which hybridize under stringent conditions to the nucleotide sequences shown in FIG. 1, FIG. 3, FIG. 5, FIG. 8 or FIG. 10. The invention further provides nucleic acid sequences encoding fragments or the complement of the polynucleotide sequences, as well as expression vectors and host cells comprising polynucleotides that encode HOMPS.
The invention further provides methods for detecting the presence and status of HOMPS polynucleotides and proteins in various biological samples, as well as methods for identifying cells that express HOMPS. A typical embodiment of this invention provides methods for monitoring HOMPS gene products in a tissue sample having or suspected of having some form of growth disregulation such as cancer.